The present invention relates to means for connecting and disconnecting electrical conductors to and from wiring devices and, more particularly, to wiring devices having novel and improved means for push-wire type connection and release of conductors.
Wiring devices such as wall switches, receptacles, and the like, are adapted for connection in a wiring circuit by connection thereto of line, neutral, and sometimes grounding conductors. Typically, the wiring device includes means for connection thereto of the conductors in one or both of two ways, namely, by securing a bare end of the conductor to the appropriate terminal or bus by a screw, and/or by so-called push-wire connection means. A wiring device equipped for push-wire connection typically includes a housing for the electrical components with openings through which the bare ends of the conductors are pushed. A spring clip is positioned inside the housing, adjacent to the opening and urges the end of the conductor inserted through the opening into tight engagement with the terminal or bus.
Push-wire connection of conductors to wiring devices is normally faster and easier than screw-type connection. Once the insulation has been stripped from the end of the conductor, it may be electrically connected to the device simply by insertion through the proper opening. In order to ensure a secure connection, the spring clip which receives the end of the conductor is designed to permit movement of the conductor only in the inward direction. That is, the spring clip is deflected as the end of the conductor is pushed through the opening in the housing, between the clip and the terminal, and engages the conductor in a manner preventing movement in the opposite direction. In order to disconnect the conductor from the device the spring clip must be deflected outwardly to release it from engagement with the conductor.
It is a common practice in conventional wiring devices equipped for push-wire connection to provide an additional opening adjacent each of the openings through which the ends of the conductors may be inserted. A tool such as the tip of a screwdriver, or the like, may be inserted through the additional opening to engage and deflect the spring clip outwardly, causing it to release the end of the conductor and permit its withdrawal from the wiring device. Although providing an effective means for disengaging and removing the conductor, it is possible that the tool may be inserted with excessive force, or in an otherwise improper manner, resulting in damage to the spring clip or other components of the wiring device. Furthermore, the presence of the unobstructed openings for tool insertion raises the possibility that other objects may be inserted through such openings with potential damage to the wiring device and/or electrical shock to the person effecting such insertion.
The prior art includes wiring devices having permanently installed release means for push-wire connections. For example, in some of the disclosed embodiments, U.S. Pat. No. 4,768,976 includes outwardly projecting tabs on a lever which may be pressed to move the spring contact out of gripping engagement with the conductor in a terminal block. In U.S. Pat. No. 3,977,751, the arms of a U-shaped, plastic member engage the springs holding push-wire connections of a portable electric tool switch assembly. U.S. Pat. Nos. 3,152,851 and 4,149,766 both disclose manually operable wire release means integral with a wiring device wherein the operating member is pivotally mounted on the housing or casing. U.S. Pat. No. 3,152,851 also mentions, without providing a specific disclosure, that sliding rather than pivoting movement may be used to transmit the release force.
It is a principal object of the present invention to provide novel and improved means for effecting safe and easy removal of a conductor from a push-wire connection with an electrical terminal.
A further object is to provide an electrical wiring device having means for effecting push-wire connection of conductors, wherein there are no unobstructed openings for insertion of objects to release the conductor connections.
Another object is to provide an electrical wiring device having integrally mounted, reciprocally slidable members which permanently block access to the interior of the device housing through openings in which the members are mounted for selective movement to release push-wire connections of conductors to the device.
Other objects will in part be obvious and will in part appear hereinafter.